Parasite Ct Copy Number

Back-calculate parasite copy concentration from a supplied Ct calibration and extraction volumes.

Description

Quantitative PCR calibration relates cycle threshold to log10 copies per reaction.

Quantitative PCR calibration relates cycle threshold to log10 copies per reaction. Dilution and specimen-volume accounting then convert reaction copies to a specimen concentration.

The tool returns copiesPerReaction (copies per reaction); copiesPerMlSpecimen (copies per ml specimen). Input measurements and model parameters are supplied by the caller; the tool computes the stated summary rather than acquiring those measurements.

When to use Parasite Ct Copy Number

Use Parasite Ct Copy Number when you already have sampleCt, calibrationIntercept, calibrationSlope, extractionVolumeUl, templateVolumeUl, specimenVolumeMl and want copiesPerReaction, copiesPerMlSpecimen. This is useful for checking a supplied calculation, documenting a measurement convention, or comparing observations prepared on the same basis.

How to use Parasite Ct Copy Number and understand its results

Enter sampleCt, calibrationIntercept, calibrationSlope, extractionVolumeUl, templateVolumeUl, specimenVolumeMl using the field table below. Match the units, ordering and data boundaries described in the calculation.
Run the tool after checking the stated bounds and matching paired observations or categories. A malformed request gives a tool error rather than a usable measurement.
Read copiesPerReaction, copiesPerMlSpecimen. Use the calculation and interpretation below to distinguish amounts, ratios, signs and decision flags where applicable.
Review the supplied parameters and assumptions before using the result in a report or comparing it with another observation.

Input field	Meaning	Value type and bounds	Requirement
sampleCt	Sample ct	number	Required
calibrationIntercept	Calibration intercept	number	Required
calibrationSlope	Calibration slope	number	Required
extractionVolumeUl	Extraction volume ul	number	Required
templateVolumeUl	Template volume ul	number	Required
specimenVolumeMl	Specimen volume ml	number	Required

Use a negative fitted calibration slope and positive volumes, with template volume no larger than extraction volume. Extraction and template volumes share the same unit; specimen volume is in mL.

reaction copies = 10^((Ct − intercept)/slope); copies/mL = reaction copies × extractionVolume/templateVolume/specimenVolume

The symbols refer to the supplied quantities or generated values described above; unit conversions and comparison boundaries follow the stated implementation.

json

{
  "input": {
    "sampleCt": 20,
    "calibrationIntercept": 30,
    "calibrationSlope": -3.3333333333333335,
    "extractionVolumeUl": 100,
    "templateVolumeUl": 5,
    "specimenVolumeMl": 1
  },
  "output": {
    "copiesPerReaction": 1000,
    "copiesPerMlSpecimen": 20000
  }
}

Limitations and assumptions

Calibration, inhibition, extraction efficiency and uncertainty are supplied or handled elsewhere. Ct alone does not prove organism viability or disease severity.

Numerical inputs must be finite. The tool checks its declared input shape and calculation constraints; those checks do not verify the quality, calibration or representativeness of the supplied observations.

Alternative or Complementary methods

ELISA Cutoff Index: Calculate a blank-corrected ELISA cutoff index using the supplied assay cutoff. Multiplex Target Decode: Decode multiplex target detections while preserving the supplied assay-control validity flag.

Methodological background: MIQE Guidelines: minimum information for publication of quantitative real-time PCR experiments.^[1]

References

MIQE Guidelines: minimum information for publication of quantitative real-time PCR experiments — Bustin et al.; Clinical Chemistry

Similar or alternative tools

ELISA Cutoff Index
Calculate a blank-corrected ELISA cutoff index using the supplied assay cutoff.
Multiplex Target Decode
Decode multiplex target detections while preserving the supplied assay-control validity flag.